Half to j



(No Model.)

G. A. SGHOLER. CHUCK FOR WATCH onowns.

Patented Jan. 21, 1896.

AN DREW EGRAHAM. PNUTlIIl-ITMIWASNINGI'ONJIC.

UNITED STATES PATENT OFFICE.

GUSTAVE A. SCIIOLER, OF SPOKANE, IVASI-IINGTON, ASSIGNOR OF ONE- I'IALFTO J. O. STUTZ, OF SAME PLACE.

CHUCK FOR WATCH-CROWNS.

SPECIFICATION forming part of Letters Patent No. 553,265, dated January21, 1896.

Application filed June 30, 1894. Serial No. 516,234. (No model.)

To all whom it may concern:

Be it known that I, GUSTAVE A. SCHOLER, a citizen of the United States,residing at Spokane, in the county of Spokane and State of \Vashington,have invented a new and useful Chuck for VVatch-Crowns, of which thefollowing is a specification.

My invention relates to crown-chucks for use in connection withwatohmakers lathes, and the object in View is to provide a chuck whichis adapted to hold watch-crowns of different sizes without adjustment,replacement or alteration of the back-rest or center; to provide a solidor single-piece back-rest or center to simplify the construction andavoid attachment, and, furthermore, to provide means for adapting theadjustable-cap of the chuck to fit crowns of different sizes, suchadjustment being facilitated by washers or filling-pieces interposedbetween the cap and the surface of the crown-piece, and beingunconnected with the cap to provide for adjusting the latter withoutturning the washer or washers upon the surface of the crown.

Further objects and advantages of the invention will appear in thefollowing description,and the novel features thereof will beparticularly pointed out in the appended claim.

In the drawings, Figure 1 is a perspective View of a chuck embodying myinvention, a watch-crown being shown in operative position therein. Fig.2 is a longitudinal section of the same. Fig. 3 is a detail view inperspective of the chuck-head and integral stem. Fig. 4 is a similarview of the cap detached. Figs. 5 and 6 are detail views in section ofwashers having diiferent interior measurements.

Similar numerals of reference indicate corresponding parts in all thefigures of the drawings.

Zdesignates the head or body portion of the chuck, which is preferablyformed integral with the stem 2, said stem being adapted to be attachedin any suitable or preferred manner to a lathe. In the constructionillustrated the stem 2 is provided with a threaded terminal 3 engaging athreaded opening in the lathe, a portion of which is shown at 4:, andthe stem being held from rotation by means of a key 5, which is arrangedin a keyway 6.

The head or body portion of the chuck is exteriorly cylindrical and isthreaded, as shown at 7 for engagement with the interior threads of anadjustable cap 14, and said head is provided with a solid conicalback-rest or center 8, formed by providing a cavity in the head orbodyportion. The conical construction of the back-rest or center adaptsit to receive and bear firmly against the surface of a crown 10 of anysize, said crown being provided in the construction illustrated with ashank 9.

It will be seen that the smaller the crown the farther it will pass intothe back-rest or center before bearing firmly against the surface ofsaid rest or center, and hence it is necessary to provide for adjustmentof the cap 14 in order to cause the inturned peripheral lip 15 of thecap to bear against the outer portion of the surface of the crown, theedge of said lip being beveled or flared inwardly to agree with thecurvature or convexity of the surface of the crown.

Inasmuch as the extent of the adjustment of the cap is limited by thearrangement of the screw-threads which connect it to the head or bodyportion of the chuck, it is necessary to provide washers orfilling-pieces 16 to fit within the cap. These filling-pieces, differentsizes of which are shown in Figs. 5 and 6, have beveled interior facesto agree with the curvature of the surface of the crown and fiat outersides to bear against the inner surface of the lip 15, and said washersare of such a construction that the pressure of their inner faces uponthe surface of the crown is sufficiently firm to hold the crown securelyin place without injuring or marring its surface. After a washer of asuitable interior diameter has been arranged in the cap and the latterhas been threaded upon the head or body portion of the chuck to bringthe inner face of the washer in contact with the surface of the crown,said washer remains stationary or free fromrotary motion during thefurther adjustment of the cap to cause the necessary firmness orpositiveness of pressure.

Under ordinary circumstances I prefer that the lip of the cap shall notcome in contact with the surface of the crown for the reason that thenecessary rotation of the cap during its adjustment causes frictionalcontact between said lip and the crown or between the crown and theback-rest or center, either of which is objectionable in that it isliable to mar the surface of the crown. Therefore I prefer to employ thewashers which remain I stationary with the crown and allow the cap torotate therearound during adjustment, and by providing a number ofwashers of different interior diameters the desired pressure upon acrown of any ordinary size may be secured.

From the above description it willbe seen that no adjustment of theback-rest or center is necessary. This simplifies the construction ofthe chuck and obviates the necessity of one means of adjustmentordinarily employed in devices of this class. Furthermore a solidback-rest or center provides a more firm and effective seat for thecrown than an adjustable back-rest or center or a back-rest or centerhaving an adjustable part or member, and this firmness is still furtherincreased by forming the head or body portion of the chuck integral withthe stem by which it is secured to the lathe.

The above construction obviates the necessity of providing a number ofheads 1 of ordinary sizes, such a construction being common when thehead or back-rest is not provided with an adjustable part or member.

Various changes in the form,proportion and the minor details ofconstruction may be resorted to without departing from or sacrificingany of the advantages of this invention.

Having described my invention, I claim As an improved article ofmanufacture, the herein specified watchmakers chuck, comprising a stemhaving an exteriorly-threaded head formed in its outer face with aninwardly-extending conical cavity whose converging walls adapt thedevice for different sized crowns, and an interiorly-threaded cap toscrew upon the said head having an inturned lip which is'beveled in anopposite direction to the converging walls of the conical concavity,jointly with different sized washers removably and interchangeablyfitted within the cap and lying wholly within the plane of the saidinturned lip,each washer being beveled to correspond with the bevel ofthe said inturned lip and in an opposite direction to the convergingwalls of the aforesaid conical concavity, substantially as described.

In testimony that I claim the foregoing as my own I have hereto affixedmy signature in the presence of two witnesses.

GUSTAVE A. SOHOLER.

W'itnesses J. C. STUTZ, HATTIE L. MERRYWEATHER.

